HID Conversion Kits.

Was wanting to upgrade my headlights, and just get a 8000k HID Conversion kit. which is better, the Standard ballast, or the Slim ballast? and where is the best place to put the ballast's in a 2002 jetta vr6. not a lot of room under the hood. and also someone at the VW dealership said that sometimes with the HID conversion kit, that inside your car a light will come on inside the dash saying the headlight is out because its a different wattage? is this true? and can you get around it? he said there is a adapter that goes on the kits you can get but i don tknow where to get it. any advice anyone?